1. Field of the Invention
The present invention relates to the field of structural separation mechanisms. More particularly, the present invention relates to the field of manually or remotely controlled fasteners utilizing a segmented threaded nut for releasibly engaging a threaded bolt.
2. Description of The Prior Art
Separation nuts are widely used in manufacturing and construction industries. The main purpose of utilizing separation nuts is to fasten threaded bolts in a quick releasible manner. Such separation nuts are traditionally known as "quick nuts". The following prior art references are relevant to the field of the present invention:
1. U.S. Pat. No. 2,489,613 issued to Beswick on Nov. 29, 1949 for "Quick Action Nut" (hereafter "the Beswick Patent").
2. U.S. Pat. No. 2,576,579 issued to Donovan on Nov. 27, 1951 for "Cone Grip Lock Nut" (hereafter "the Donovan Patent").
3. U.S. Pat. No. 3,160,187 issued to Zahodiakin on Dec. 8, 1964 for "Quick Locking Fastener With Single Movable Jaw" (hereafter "the Zahodiakin Patent").
4. U.S. Pat. No. 4,875,266 issued to Batten on Oct. 24, 1989 for "Releasable High Torque Fastener" (hereafter "the Batten Patent").
5. U.S. Pat. No. 4,930,961 issued to Weis on Jun. 5, 1990 for "Quick Lock And Release Fastener" (hereafter "the Weis Patent").
The Batten Patent discloses an easily releasable fastener specially designed for high torque applications. The Batten Patent fastener comprises a washer, a nut and a retaining ring. The nut has three threaded segments all retained by the retaining ring. A threaded bolt can be threaded into the three-segmented nut, and the retaining ring acts to keep the fastener as a unit. The Batten Patent also comprises a retractor for removing the retaining ring to release the bolt. The Batten Patent has disclosed the feature of utilizing a three-segmented nut. However, the retaining ring of the Batten Patent is a unitary piece which can only be manually removed with the retractor.
The Weis Patent discloses a quick lock and release fastener. The Weis Patent fastener comprises a split threaded nut operable within a drive plate and an operating head fixed with the drive plate. The split nut and the drive plate have cam engagement for constriction into threaded engagement and alternate separation with a bolt. A semi-circular compression spring is provided for facilitating the separation of the two segments of the split nut. The Weis Patent also has not disclosed any segmented retaining means which can be automatically fastened or released through the function of a retaining wire.
The Beswick Patent discloses a quick action nut having a three-segment internal nut contained in an outer member or housing. Each segment of the split nut is independently engaged with a spring biased pin. The segments of the split nut further have outer ribs which are engageable with the inner grooves of the housing. Again, the Beswick Patent has not disclosed the feature of utilizing segmented retaining means for facilitating automatic fastening or releasing of an installed threaded bolt.
The Donovan Patent discloses a quick grip lock nut utilizing a three-segmented nut adapted to secure the skin of airplane wings.
The Zahodiakin Patent discloses a quick locking nut with a self-contained coil spring for biasing a movable clamping jaw.
It can be seen that many prior art quick nuts have utilized a segmented threaded nut. Typically, the segmented threaded nut includes three threaded segments. To retain a threaded element such as a threaded bolt, the threaded segments are tightened together by various means, including a circular sleeve, a cam disc, a biasing spring, etc. To release the threaded bolt, the threaded segments are loosened. Traditional separation nuts are often released by manual and local operations.
However, in many situations such as in aerospace applications, it is often required that the releasing of the separation nuts be manually and remotely controlled. One type of separation nut used in the aerospace industry utilizes explosive initiators such as squibs for a remotely controlled release, and are known as "explosive separation nuts". However, in many aerospace apparatus such as satellites, it is highly desirable to employ separation nuts which utilize a quick and easy fastening and releasing of the releasing mechanism because the separation nuts are located very close to highly sensitive electronic modules.
Another requirement in aerospace applications is that the initiation or release of the retaining wire must create no shock to the system. The prior art explosive device often creates a pyrotechnic shock wave to the system, and therefore is highly undesirable.
In addition to the requirement that the separation be performed in a wire-wrapped segmented spool, the separation nuts used in aerospace applications must also satisfy other critical requirements. For example, the separation nuts often need to be very small (such as less than one inch long) and very lightweight (such as a few ounces), but must be able to tolerate a very high tensile load (such as up to ten thousand pounds). Therefore, it is highly desirable to have a very efficient and also very effective design and construction of a new separation nut which can be used in various applications, particularly in the aerospace industry.